Conventionally, a spin coating method has been known as a coating method in which a coating liquid is applied on a substrate such as, for example, a semiconductor wafer or a glass substrate. The spin coating method refers to a method of forming a coating film by dropping a coating liquid from a nozzle onto a central portion of the substrate while rotating the substrate so that the coating liquid is diffused on the substrate by a centrifugal force and spread to be coated on the substrate to form a coating film.
In the spin coating method, most of the coating liquid dropped out onto the substrate is scattered out of the substrate. Thus, the usage efficiency of the coating liquid tends to be low. Therefore, a slit coating method has recently been proposed as a coating method to replace the spin coating method.
The slit coating method refers to a method of coating using a nozzle having a slit-like discharge port. Specifically, in the slit coating method, a coating liquid, which is slightly exposed from the discharge port of the nozzle is brought into contact with a substrate and in this state, the nozzle and the substrate are relatively moved such that the coating liquid is spread and coated on the substrate to form a coating film. According to the slit coating method, the utilization efficiency of the coating liquid may be enhanced because the coating liquid can be applied on the substrate as needed. See, e.g., Japanese Patent Laid-Open No. 2011-167603.